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Biofilm formation at the solid-liquid and air-liquid interfaces by Acinetobacter species

Martí S, Rodríguez-Baño J, Catel-Ferreira M, Jouenne T, Vila J, Seifert H, Dé E - BMC Res Notes (2011)

Bottom Line: The members of the genus Acinetobacter are Gram-negative cocobacilli that are frequently found in the environment but also in the hospital setting where they have been associated with outbreaks of nosocomial infections.This ability was generally higher at 25°C which might contribute to their persistence in the inanimate hospital environment.Our work has also demonstrated for the first time the ability of the members of the ACB-complex to form biofilm at the air-liquid interface, a feature that was not observed in other Acinetobacter species.

Affiliation: Laboratory "Polymères, Biopolymères, Surfaces", University of Rouen, UMR 6270 & FR 3038 CNRS, IFRMP23, Mont-Saint-Aignan, France. saramarti2@yahoo.es.

ABSTRACT

Background: The members of the genus Acinetobacter are Gram-negative cocobacilli that are frequently found in the environment but also in the hospital setting where they have been associated with outbreaks of nosocomial infections. Among them, Acinetobacter baumannii has emerged as the most common pathogenic species involved in hospital-acquired infections. One reason for this emergence may be its persistence in the hospital wards, in particular in the intensive care unit; this persistence could be partially explained by the capacity of these microorganisms to form biofilm. Therefore, our main objective was to study the prevalence of the two main types of biofilm formed by the most relevant Acinetobacter species, comparing biofilm formation between the different species.

Findings: Biofilm formation at the air-liquid and solid-liquid interfaces was investigated in different Acinetobacter spp. and it appeared to be generally more important at 25°C than at 37°C. The biofilm formation at the solid-liquid interface by the members of the ACB-complex was at least 3 times higher than the other species (80-91% versus 5-24%). In addition, only the isolates belonging to this complex were able to form biofilm at the air-liquid interface; between 9% and 36% of the tested isolates formed this type of pellicle. Finally, within the ACB-complex, the biofilm formed at the air-liquid interface was almost 4 times higher for A. baumannii and Acinetobacter G13TU than for Acinetobacter G3 (36%, 27% & 9% respectively).

Conclusions: Overall, this study has shown the capacity of the Acinetobacter spp to form two different types of biofilm: solid-liquid and air-liquid interfaces. This ability was generally higher at 25°C which might contribute to their persistence in the inanimate hospital environment. Our work has also demonstrated for the first time the ability of the members of the ACB-complex to form biofilm at the air-liquid interface, a feature that was not observed in other Acinetobacter species.

ALI-biofilm formation by A. baumannii. a) the positive strain forms a pellicle on the top of the liquid media and the culture broth remains transparent; b) pellicle observed from above; c) inversed tube shows the pellicle strength.
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Figure 1: ALI-biofilm formation by A. baumannii. a) the positive strain forms a pellicle on the top of the liquid media and the culture broth remains transparent; b) pellicle observed from above; c) inversed tube shows the pellicle strength.

Mentions: ALI-biofilm formation was performed in 5 ml polystyrene tubes with a diameter of 12.8 mm; biofilm formation was determined in Mueller Hinton broth (Oxoid, France) using an initial OD600 of 0.01 and incubated at 25°C or 37°C for 72 h without shaking. Positive ALI-biofilm samples were identified visually (Figure 1); the isolates were considered positive when a pellicle was covering the whole liquid surface.

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Biofilm formation at the solid-liquid and air-liquid interfaces by Acinetobacter species

Martí S, Rodríguez-Baño J, Catel-Ferreira M, Jouenne T, Vila J, Seifert H, Dé E - BMC Res Notes (2011)

ALI-biofilm formation by A. baumannii. a) the positive strain forms a pellicle on the top of the liquid media and the culture broth remains transparent; b) pellicle observed from above; c) inversed tube shows the pellicle strength.
© Copyright Policy - open-access
Figure 1: ALI-biofilm formation by A. baumannii. a) the positive strain forms a pellicle on the top of the liquid media and the culture broth remains transparent; b) pellicle observed from above; c) inversed tube shows the pellicle strength.
Mentions: ALI-biofilm formation was performed in 5 ml polystyrene tubes with a diameter of 12.8 mm; biofilm formation was determined in Mueller Hinton broth (Oxoid, France) using an initial OD600 of 0.01 and incubated at 25°C or 37°C for 72 h without shaking. Positive ALI-biofilm samples were identified visually (Figure 1); the isolates were considered positive when a pellicle was covering the whole liquid surface.

Bottom Line: The members of the genus Acinetobacter are Gram-negative cocobacilli that are frequently found in the environment but also in the hospital setting where they have been associated with outbreaks of nosocomial infections.This ability was generally higher at 25°C which might contribute to their persistence in the inanimate hospital environment.Our work has also demonstrated for the first time the ability of the members of the ACB-complex to form biofilm at the air-liquid interface, a feature that was not observed in other Acinetobacter species.

Affiliation: Laboratory "Polymères, Biopolymères, Surfaces", University of Rouen, UMR 6270 & FR 3038 CNRS, IFRMP23, Mont-Saint-Aignan, France. saramarti2@yahoo.es.

ABSTRACT

Background: The members of the genus Acinetobacter are Gram-negative cocobacilli that are frequently found in the environment but also in the hospital setting where they have been associated with outbreaks of nosocomial infections. Among them, Acinetobacter baumannii has emerged as the most common pathogenic species involved in hospital-acquired infections. One reason for this emergence may be its persistence in the hospital wards, in particular in the intensive care unit; this persistence could be partially explained by the capacity of these microorganisms to form biofilm. Therefore, our main objective was to study the prevalence of the two main types of biofilm formed by the most relevant Acinetobacter species, comparing biofilm formation between the different species.

Findings: Biofilm formation at the air-liquid and solid-liquid interfaces was investigated in different Acinetobacter spp. and it appeared to be generally more important at 25°C than at 37°C. The biofilm formation at the solid-liquid interface by the members of the ACB-complex was at least 3 times higher than the other species (80-91% versus 5-24%). In addition, only the isolates belonging to this complex were able to form biofilm at the air-liquid interface; between 9% and 36% of the tested isolates formed this type of pellicle. Finally, within the ACB-complex, the biofilm formed at the air-liquid interface was almost 4 times higher for A. baumannii and Acinetobacter G13TU than for Acinetobacter G3 (36%, 27% & 9% respectively).

Conclusions: Overall, this study has shown the capacity of the Acinetobacter spp to form two different types of biofilm: solid-liquid and air-liquid interfaces. This ability was generally higher at 25°C which might contribute to their persistence in the inanimate hospital environment. Our work has also demonstrated for the first time the ability of the members of the ACB-complex to form biofilm at the air-liquid interface, a feature that was not observed in other Acinetobacter species.

View Similar Images In: Results  - Collection
View Article: MedlinePlus - PubMed Central - HTML -  PubMed
Show All Figures - Show MeSH
getmorefigures.php?pmc=3023692&rFormat=json&query=the&fields=all&favor=none&it=none&sp=none&sub=none&req=5